Alexander Graham Bell is best remembered for inventing the telephone, but the great Scottish inventor’s interests weren’t limited to just one field. Aside from his priceless contributions in the field of acoustics and telegraphy, Bell is also credited with the invention of the metal detector, the audiometer (an instrument used to detect hearing problems), and a device to locate icebergs. Bell and his associates investigated the possibility of impressing a magnetic field on a physical device as a means of recording sound—the basic principle behind tape recorder and hard disc—but could not develop a workable prototype. Bell also had a great passion for aeronautics.

July 7, 1908. Alexander Graham Bell (right) and his assistants observe the flight of a circular tetrahedral kite.